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NADT!

Started by madbean, March 18, 2015, 11:25:26 PM

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rullywowr

I'm more of a 1990s vintage Crate solid state GX15 fan for the ultimate toan.



  DIY Guitar Pedal PCB projects!

Betty Wont

NAW man, toanz are in the Smokey Amp. But you gotta use an attenuator to tame the mass.

pryde

I picked this baby up used for a steal at $600 off of some sucker. The organic, third-order harmonic content is sick. TOANZ MAN!


peAk

Quote from: rullywowr on March 19, 2015, 02:11:44 PM
I'm more of a 1990s vintage Crate solid state GX15 fan for the ultimate toan.


hey now....my first amp in the late 80's


Govmnt_Lacky

Can any of you TGP'ers please let me know where I can find the madbean forum?  ::)

madbean

I spent some time with the amp today and here is my report.

Quality:
Sweetwater double boxed with plenty of cushion, so the amp arrived in perfect shape. Pretty much what I expect from them.
Build quality on the exterior is good. It's not the greatest of all tolexing jobs but it is certainly good enough. No extra flaps, glue marks, etc.
Aesthetics are just as I expected. I like the silverface look and drip edge. It matches the vintage Champ I have.

Sounds:
Tremolo - Just great overall. Lush and deep enough with a good range of speed. With the depth turned toward max and moderate speed it starts to get into rounded square wave but more sine at slower speeds. I like it fine.
Reverb - My first tube amp with reverb. I will never set it above "3" probably but it's good enough for me. Not the lushest reverb I have ever heard but plenty great. I'm no expert on spring driven reverb so there's that.
Headroom - Plenty of it for testing purposes. At around 4-5 it starts to break up. I did not turn it past 8 so far but it really starts to overdrive at that point.
Noise: Not totally quiet but not terribly noisy either. I tested with single coils and humbuckers. The outlet I'm on is not the greatest either but most of the noise was 60 cycle which is what I would expect. Noise does increase a bit with the treble pot turned at max.

And here is where I'm a little disappointed: this amp has just too much bass. I mean, an ungodly amount for me. Even with the bass turned all the way down I still want to go about another 30%. It's bassier than my AC15 which has a 12"! The problem with that is it accentuates the relatively scooped mids even more which I don't like. It was enough to consider returning it which I did for a while.

However, I did some more reading and it seems as though others had the same initial impression but changed their minds as the speaker broke in. At least a few people said after break in the mega bass more or less went away and the harmonics and richness come out a lot more. I also took a look at the factory schem and saw that there is an 18k resistor between the bass pot and the mid setting resistor. So, this could be jumpered to reduce bass further. I think I'm okay with that since it would only require a wire jumper and not any swapping of components (which I don't want to do on a brand new amp).

So, I'm gonna sit on it for a couple of more days and decide whether or not to put in for the long haul or pull up the anchor. I think if the bass can be brought under control then it will be a fine amp for what I need it to do.

culturejam

Nice! Glad you mostly like it. I'm sure you can either wait on the break in period or change a component value or two to get where you want.
Partner and Product Developer at Function f(x).
My Personal Site with Effects Projects

pryde

Pretty common complaint with the little PR amps. Reducing fist stage cathode bypass cap and phase inverter input cap values is pretty common on these and can get you there.

cooder

Quote from: pryde on March 20, 2015, 01:50:38 AM
Pretty common complaint with the little PR amps. Reducing fist stage cathode bypass cap and phase inverter input cap values is pretty common on these and can get you there.

This will make a great difference if you decide to keep the amp and are happy to change things inside a bit.
Here's a great calculator to check out what value of bypass capacitor might work better for you; Fenders often use a 22 uF cap there which gives a very low end strong bass response in V1.
It may be better to use something like 1 uF or 0.68uF (typical Marshall value) there.
Here's the calculator:
http://www.ampbooks.com/mobile/amplifier-calculators/cathode-capacitor/
http://www.ampbooks.com/mobile/amplifier-calculators/cathode-capacitor/calculator/
and here's a great vid by legend Uncle Doug about the whole shebang:
BigNoise Amplification

selfdestroyer

Quote from: peAk on March 19, 2015, 01:43:36 AM
Quote from: madbean on March 19, 2015, 01:16:58 AM
Quote from: rullywowr on March 19, 2015, 01:12:49 AM
Me too. After watching the demo vids on YouTube, the black is what I thought I wanted but the silver sounds so much better.  A bit wary of some of the early build issues I've heard but I think they have it sorted. Let us know how you like it!

I think they both sound pretty great but the silver with its early breakup is more what I need. As far as build issues, who knows. People always say that about PCB fabbed amps and while I definitely would prefer turret board that seems to be harder to come by outside the realm of boutique builders. I don't know why the silver is made in Mexico and the black is made in the US, though. But hey, Mexican Strats are pretty good, so...

Yeah, .....I actually like the look of the Silverface better for some reason.

Didn't someone here just get one......umm, was it Cody?

Anyway, Congrats. Princetons are sweet. I want one so bad.

I did and I love the thing... surpassed my expectations. It is pretty bassy but I have really come to like it.

porn shot


Come one Brian, lets see yours.

Side note, do you get any hum when you turn your reverb up past 4 or 5? I need to pull the tube to see if it goes away but been to busy to mess with it right now.

Cody

madbean

cooder, thanks for the links! I love Uncle Doug.

I plugged into the DTSC for a comparison. Comparing the '68 Princeton TS with the bass set to zero and then changing the bass pot to 268k and setting it to about 7% up. It's a pretty striking difference...a little less than 10dB @ 100Hz. So, could be that all I need is to bypass that 18k stopper resistor to get it where I want.

I'll get a pic up later today of the amp.


madbean

Super fun stereo setup.

peAk


Quote from: madbean on March 20, 2015, 05:35:56 PM
Super fun stereo setup.

Was that a hint that you are going to start working on some stereo designs?

:D

pryde

Dig that Reverend. Thought about snagging one of those.

alanp

Put them on opposite sides of the room for more mindblowingly stereo :)
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